As the U.S. Justice Department moved to investigate the legality of criminal prosecution of school-skipping students in Dallas, a state Senate panel advanced a controversial plan to limit the involvement of criminal courts in enforcing truancy.

But even if a bill by Sen. John Whitmire, D-Houston, should eventually pass — it faces strong opposition from some county officials — a key lawmaker said Wednesday it will not solve the problems federal officials will be examining. The Senate Criminal Justice Committee passed the bill 6-0 Tuesday.

“The bill is an improvement, and I support it for that reason, but it’s not decriminalization,” said state Sen. Rodney Ellis, D-Houston, who has requested a Justice Department investigation in Fort Bend County and applauded the federal inquiry in Dallas.

“By criminalizing truancy, it adversely affects minority and special education students disproportionately … the Texas truancy system is pushing students who often face economic and social hardships out of school and further away from those opportunities,” Ellis said.

The Justice Department inquiry “will focus on whether the courts provide constitutionally required due process to all children charged with the criminal offense of failure to attend school, including whether those protections apply to children whom the county charges with contempt,” the department said in a statement Tuesday.

Dallas County, one of two in the state in which failure to attend school is prosecuted in a dedicated truancy court, prosecuted about 20,000 cases in fiscal year 2014, more than 20 percent of the state total, according to the Legislative Budget Board.

“This investigation continues the Justice Department’s focus on identifying and eliminating entryways to the school-to-prison pipeline, and illustrates the potential of federal civil rights law to protect the rights of vulnerable children facing life-altering circumstances,” Attorney General Eric Holder said in the statement. “As the investigation moves forward, the Department of Justice will work to ensure that actions of Dallas County’s courts are appropriate; that our constitutional protections are respected; and that the children of Dallas County can receive the meaningful access to justice that all Americans deserve.”

Investigators also will look into the county’s juvenile district courts and whether children with disabilities have “meaningful access to the judicial process.”

Texas is one of two states that charges students in adult criminal court for skipping school, according to the nonprofit advocacy group Texas Appleseed, which was among the groups that filed the 2013 Department of Justice complaint alleging that Dallas County’s truancy courts violate students’ civil and constitutional rights.

Ellis asked the Justice Department on March 18 to investigate racial disparities in the application of Texas truancy laws, particularly in the Fort Bend Independent School District. Fort Bend County is the other Texas county with a dedicated truancy court.

The Houston Chronicle reported in March that half of the high school students criminally charged with truancy in the Fort Bend ISD last year were black and 30 percent of them Hispanic, though they made up 32 and 23 percent of the high school student body, respectively.

During a Capitol hearing on Tuesday, those in favor of Whitmire’s bill argued that low-income and minority students are targeted by a system that needlessly forces them into the criminal justice system. Opponents said court intervention is needed in many cases to keep children in school.

Under current law, students with three unexcused absences in four weeks — or 10 in six months — may be charged with “failure to attend school,” a class C misdemeanor prosecuted in adult criminal court, and could face fines up to $500. In most states, truancy is handled in juvenile or civil courts.

According to Texas Appleseed, which supports decriminalization, Texas prosecuted more than 115,000 of these “failure to attend school” cases in fiscal year 2013, more than twice the number in all other states combined.

Texas Supreme Court Chief Justice Nathan Hecht, testifying to the Criminal Justice Committee, weighed in on the side of decriminalizing truancy, noting that Texas has “a real problem with keeping kids in school.”

While Whitmire’s bill would not fully decriminalize truancy, he said it would allow students to develop a behavior-improvement plan in cases where they face expulsion by a court. It would also reduce the fine for a first offense to $100; fines would increase by $100 for each subsequent offense up to a maximum of $500. In addition, it would require schools to designate someone to implement truancy prevention measures.

Opponents insisted that courts are the proper place to deal with some students who chronically skip school. An angry Whitmire blasted back, accusing one Tarrant County vendor of unregistered lobbying against his bill and noting that civil courts might still be involved.